1. Technical Field
The present invention relates to a semiconductor integrated circuit and a method of controlling an internal voltage of the same.
2. Related Art
A semiconductor integrated circuit uses various voltage levels, and power can be divided into two main types: external power (VDD and VSS) and internal power (VPP and VBB).
In other words, external power is supplied by an apparatus having a semiconductor integrated circuit mounted thereon, and internal power is supplied by converting the external power in the semiconductor integrated circuit.
In ascending order, the voltage levels are VPP, VDD, VSS, and VBB. VBB is a reverse bias voltage having an absolute value larger than that of the ground voltage VSS.
VPP is essentially used in a word line driver and a data-out driver in order to compensate for threshold voltage loss in a transistor constituting a memory cell of an integrated circuit. VPP is generated by boosting VDD and has a value larger than the sum of VDD and the threshold voltage VT.
The stability of the above-mentioned internal power has a great impact on the reliability and current consumption of a semiconductor integrated circuit. Therefore, in the design of a semiconductor integrated circuit, it is important to provide a stable supply of power within a predetermined range by controlling the power supply.